Elevator



(No Model.)

W. O. BAIRD.

ELEVATOR.

Patented Mar. 22, 1892.

awe anew) "m: mums Penna UNITED STATES PATENT OFFICE.

- IVILLIAM O. BAIRD, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE WILSON MANUFACTURING COMPANY, OF MINNESOTA.

ELEVATOR.

SPECIFICATION forming part of Letters Patent No. 471,497, dated March 22, 1892.

Application filed May 25, 1891.

To all whom it may concern:

Be it known that I, WILLIAM C. BAIRD, of

Brooklyn, county of Kings, and State of New York, have invented a new and useful Improvement in Elevators, of which the following is a specification.

In Letters Patent of the United States No. 109,331, dated November15, 187 O,is described a combination of a chain with an elevator and a balance box connected therewith, so that by shifting the chain from the carriage to the balance-box, or vice versa, the carriage was caused to rise or descend.

In the operation of such an elevator itwas found that as the carriage ascended the running of the chain over the sheave caused its weight to be transferred from oneside of the sheave to the other, so that the weight of the chain on the side next the carriage rapidly decreased, while the weight of the chain on the side next the balance-box rapidly increased. This accelerated the upward motion. of the carriage to such a degree that it was in some cases ungovernable. The object of my present improvement is to overcome this difficulty, and I also provide a retarder, by which the maximum velocity of the carriage can be controlled either in its upward or downward course.

In the accompanying drawings, Figure 1 is an elevation, partly in section, of an apparatus containing my invention. Fig. 2 is a side view of the main shaft, with the parts mounted thereon, partly in section. 3 is an end view of the shaft from the right of Fig. 2 with the cap of the retarder removed to disclose its interior construction.

a is the carriage. b b are the ways by which it is guided up and down.

0 is the balance-box.

A b is the way between which and the Way I) the balance-box is guided up and down.

d is a box or receptacle, mounted on the carriage to receive one end of the chain.

6 is the main shaft.

f is the carriage-supporting sheave.

g is the supporting-rope, which is attached at one end to the carriage a, passes over the sheave. f, and is attached at the other end to 5c the balance-box o.

h is the chain-supportin g sheave, over which Serial No. 894.000. (No model.)

passes the chain t', one end of which is deposited in the receptacle d, and the other end I of which is deposited in the balance-box c.

j is the hand-rope sheave, over which the hand-rope 70 passes, which is endless, and at the lower end of the shaft passes under the sheaves Z and Z.

m is a chain corresponding with the chain 2', which is attached at one end to the car-.60 riage and at the other end to the balance-box, and passes under the sheaves n and n at the bottom of the shaft. I

The main shaft e may be stationary, and the sheave f runs thereon; but the sheaves h and j run upon the sleeve 0', which is secured to and moved with the sheave f. The sheaves h and j are secured firmly together and run between the collars p and p, which exert sufficient friction on their sides so that normally they will be made to rotate with the sleeve 0 by the operation of the hand-rope It.

q is the retarder, which consists of a stationary ring 0", which may be held in position by the brackets r, also a star-wheel s, secured 7 5 to and moving with the sheave f, also the friction-blocks t, t, and which are fitted loosely between the arms of the star-wheel, as shown in Fig. 3, and which are carried around Within the ring 0" by said arms, but in such motion are thrust outward against the ring by the Wedging action of the arms against them, as indicated in Fig. 3.

The operation is as follows: When the carriage is at the bottom of the shaft, it is started upward by moving the hand-rope so as to turn the sheaves h and j on the sleeve 0 until sufficient of the chain '5 has been deposited in the balance-box c and taken from the receptacle d to overbalance the Weight contained in the carriage. As the elevator goes up the length of chain from the sheave h to the balance-box 0 will increase, and that from the receptacle d to the sheave h will decrease, which, other things being equal, would have a tendency to create an accelerated motion; but this difference is exactly counterbalanced by the increase of the length of chain n between the carriage and the sheave n and the decrease of the length of chain m between the I00 balance-box and the sheave n. When it is desired to lower the carriage from the top of the shaft, the reverse operation and result take place. All movements of the carriage must be responded to by the movement of the star-Wheel s in the retarder, and since the friction exerted by the blocks H 15 against the ringr increases with the speed of the star- Wheel to such an extent as to check any abnormal speed, the speed of the carriage is lim ited Within safe bounds. These bounds may be determined by the length of the arms of the star-wheel 8, since for a given speed the longer these arms are constructed the less will be the friction exerted by the blocks 15, t, and t and vice versa.

Although I have referred to 0 and m as chains, I do not wish to limit myself strictly to that form of flexible connection, since I am WILLIAM C. BAIRD.

Witnesses J. E. GREER, FRED KEMPER. 

